Speaking to Luton Today, Hartson, who is to have a CAT scan and see a consultant in December. said: "The doctors don't want to see me until November 27, so I will have around five weeks off."
"I was having mind-blowing headaches. "It was probably the headaches that saved my life. I went to the hospital with my sister, Victoria, and I told them the headaches were not just ordinary headaches but were passing out headaches.
"I was a 19st man curled up into a ball. I spent five weeks in intensive care, had two brain operations and then chemotherapy. To be honest I still don't know the extent of it."
There is good news in that Hartson is planning to marry his pregnant partner Sarah McManus next July.